In 2004, Wu-Tang Clan reunited in full for the inaugural year of Rock the Bells. The booking was a coup for the festival with ambitions of being a prime destination for fans of the genre.

Now the festival, in its 10th year, is a preeminent showcase for hip-hop. It travels the country — reaching San Francisco, Washington, D.C., and New York — and has swelled into a two-day outing that lures 20,000 fans to a lineup of more than 60 acts.

For the festival’s landmark anniversary, Wu-Tang Clan will once again reunite in full and perform.

And the iconic hip-hop posse, celebrating 20 years together, is resurrecting its most boisterous member: Ol’ Dirty Bastard.

The infamous ODB died four months after he performed at 2004's Rock the Bells. But during Wu-Tang’s headlining slot on Sunday, Ol’ Dirty will take the stage again — as a hologram-like image.

But it doesn’t end there.

Festival organizers also engineered a virtual likeness of NWA founder Eazy-E, who passed away in 1995, to “perform” alongside his protégés Bone Thugs-N-Harmony during their set on Saturday, which coincidentally would have been the rapper's 50th birthday.

“It’s a great opportunity to be able to bridge technology in this genre of music,” said Eazy-E’s widow, Tomica Wright, who heads his estate and runs his Ruthless Records imprint. “It was also a good feeling to know that respect was there for someone to want to spend the money and time and bring back a person in that element to keep the legacy going.”

Like thousands of rap fanatics at Coachella last year, Rock the Bells founder Chang Weisberg stood in the audience, mouth agape, as Dr. Dre and Snoop Dogg resurrected their fallen comrade, Tupac Shakur, for a medley during their closing slot.

Inspired by what he saw, Weisberg immediately started to plot which rappers could virtually take the stage at Rock the Bells.

As ambitious as crafting “virtual performances” (as they are being billed) is, he wanted to take it a step further.

“At Coachella you saw what appeared to be a hologram onstage with a team recreating the face of Tupac and the body was basically like an actor captured on a green screen,” said Weisberg, the head of concert promotions and marketing firm Guerilla Union. “The actual DNA of these avatars is comprised of the family members of the late rappers.”

Weisberg teamed with AV Concepts, who were behind the Tupac hologram, and Play Gig-It, to combine green screen capture, animation and multimedia elements for the images.

But the secret weapon was working with the often-feuding late rappers' families to help perfect the animated avatars.

Eazy-E's kids Eric "Lil Eazy-E" Wright Jr., Derrick "E3" Wright and Erin Wright will constitute the body, voice and face, respectively, of the deceased NWA founder's projected image. And ODB's oldest son, Young Dirty Bastard, will embody his father for the digital performance.

“Basically I am the hologram. It's all me,” said YDB, who also has a solo slot on the festival lineup. “I did the performance and I’m also doing the voice. I’m 24 years old, so what they did was [aged] me to 27 years old, when my father was in his prime.”

“One of the unique things with YDB is he’s really able to embody his dad’s charisma, motion and style because he’s been doing tributes to him for a long time,” YDB’s manager, Messiah Jacobs, said.

“They didn’t really have to go spend that extra money because of his ability to tap into his essence,” Jacobs said. “People were clapping, people were crying because there’s a moment where he’s going to actually interact with the hologram. The hologram will be onstage and Young Dirty will be onstage. It was very emotional.”

Both ODB and Eazy-E's images will perform original music, with dubbed dialogue (YDB said he was filmed performing his father’s classics "Shimmy Shimmy Ya" and "Got Your Money").

“You’re not going to be looking at 1987 Eazy-E, you’re going to be looking at 1994, heyday," Wright said. “You’re going to get probably what most people remember of that last impression of that era he was in.”

After the plans to re-create the two rap legends were announced earlier this year, Icelene Jones, ODB’s widow filed a cease-and-desist order against Rock the Bells. Weisberg, had received the OK from ODB's mother, Cherry Jones, but the two women are battling for control of the estate and it became an issue of contention. It was quickly resolved.

“I came to learn Icelene is in control of the estate. Once we spoke with her and the estate, they were completely on board. They just were a little disappointed that no one had reached out to them initially,” Weisberg said.

“We definitely wanted it to happen,” Icelene Jones said. “We were excited, it was just that we were left out. Once we got in contact with them it started working out for the best for everybody.”

ODB’s widow said watching the digital performance being crafted was emotional, but she is pleased with the finished product, which she saw for the first time Wednesday.

“They have my son moving, but it’s my husband’s body of how he used to move. Instead of taking something that happened a long time ago they have something original,” she said. “It was remarkable. It was really nice to see my husband onstage. I couldn’t believe it.”

Wright, who was heavily involved in the creation of Eazy-E’s “hologram” said the finished product is an “accurate, authentic reflection” of her late husband.

“We aren’t trying to mimic something, you’re creating something,” she said. “We’re building, in the capacity, a reflection to carry on that’s a piece of him. It’s not going to be him, but its going to be as damn close as you can get.”